Exhaust device for explosion or internal combustion engines



July 2, 1940.

M. KADENACY' 2,206,193 Exmufi DEVICE FOR nxrno's xon on INTERNALcoususnon ENGINES 1 ori inal Filed Aug. 1, 1934 v 17 may 2' Sheets-Sheet'1 July 2, 1940.

M; KADEINACY 1 2,206,193

EXHAUST DEVICE FOR EXPLOSION OR INTERNAL COMBUSTION ENGINES OtiginalFiled Aug. 1, 1934 2 Sheets-Sheet 2 1' leaves the cylinder at a PatentedJuly '2, 1940 UNITED- STATES amiss EXHAUST DEVICE FOR EXPLOSION ORINTERNAL COMBUSTION ENGINES Michel Kadenacy, Paris, fiance Originalapplication August 1, 1934, Serial No.

738,016, now Patent No. 2,110,986, dated Mitch Divided and thisapplication February 3,'1938, Serial No. 188,555. In Great BritainDecember 13, 1933 11 Claims.

The applicant has found that in an internal combustion engine, thebehaviour of the gases is such as to lead to the conclusion that as aconsequence of the combustion 05 5 while still in the cylinder, theburnt gases form a mass having a high initial velocity and possessingproperties similar to those of a resilient body, so that when theexhaust orifice opens this mass seeb to project itself bodily from thecylinlo der and to leave the latter in a consequent vacuous condition.

The present invention relates to two-stroke cycle internal combustionengines, wherein at least a substantial portion of the burnt gases speedmuch higher than that obtaining when a flow resulting from an adiabaticexpansion only is involved and in sucha short interval of time that itis discharged as a mass, leaving a depression behind 20 it which isutilised in into the cylinder.

The applicant has also found that in the operation of such an internalcombustion engine the burnt gases do not leave the cylinder immeudiately the exhaust orifice commences to There is first a period ofdelay, during which the burnt gases do not issue from the cylinder, andafter this delay has elapsed the burnt gases issue bodily from thecylinder with an extremely high 30 velocity as a mass which responds tothe laws of reflection and rebound and it leaves in the cylinder aprofound depression. Subsequently, this outward motion of the burntgases is reversed in direction and if the gases are allowed to re-entera the cylinder they destroy the depression left therein. 1 s

In the specification of U. 8. Patent No. 2,102,559 issued December 14,1937, the applicant has described and claimed a method of ch rging two--0 stroke cycle internal combustion engines which consists in opening theinlet orifice for the introduction of a fresh charge after the exhaustorifice opens, but only with the required delay to ensure that the burntgases are then moving out:

wardiy through the exhaust system as a consequence of their mass exitfrom the cylinder and cause a suction efiect to be exerted in thecylinder. at the said inlet orifice.

In such an engine, an untimely return of the go burnt gases may have anobjectionable influence on the contents of the cylinder and the objectof the present invention, which object is also that oi theinventiondescribed in the applicants U. S. Patent No. 2,110,986, issued March 15,1938,

a from which the present application has been dithe charge, and

introducing a fresh charge vided, is to provide in the exhaust system ofan engine operating in accordance with the above method, means which areadapted to permit the free exit of the mass of burnt gases from thecylinder and to prevent the return of this mass 5 or a portion thereofof burnt gases to the cylinder by utilising the above mentionedproperties oi the burntgases.

The invention consists in the provision. within the exhaust system 'ofdeflecting means situated between the exhaust orifice and the zone inthe exhaust system from which the return of the burnt gases occurs afterthe said bodily exit from the cylinder at high velocity, the saiddeflecting means being adapted to permit the free outward movement ofthe burntgases and to preventby refiection the return of the said gasesto the cylinder.

It is to be understood that in considering the free discharge or theburnt gases losses due to no friction are excepted, but these lossesshould oi! course be kept down to a minimum.

Now if the characteristics of the exhaust system are fixed, the intervalelapsing between the bodily exit of the burnt gases from the cylinderand the subsequent reversal in direction of movement of these gases is aduration of time which is substantially constant. As a some quence, thisinterval will extend over a larger crank angle at high engine speedsthan at low engine speeds. Consequently the return of the burnt gases ismore liable to exert an objectionable influence on the contents of thecylinder at low engine speeds. It the angular separation between exhaustopening and inlet opening is also fixed, there will be a limiting'lowspeed for. which the return occurs too soon to permit the timing ofinlet opening to be operative in the required manner.

In general, therefore, the means according to Q,

the invention will have the effect of improving the operation ofi theengine at low engine speeds and of exten the possible range of workingspeeds of the e e in the direction of low speeds. i

In one embodmmt of the invention the ma deflecting means comprisesurfaces adapted to impart a whirling motion to the whole of the issuingmass of burnt gases so thatthey cannot return to the cylinder, or to aportion only of the issuing mass, while allowing the free passageottheremainderofthesaidburntgasensoas toformagaseousplugadaptedtocauseanysubsequent return wave of the said burntgases to rebound without further appreciable loss in towards thecylinder from the atmosphere it has fed with air through the duct I andwith fuel encountered, is caused to rebound again in the direction ofexhaust by the device according to the invention, the body of gasesthereby produces an additional suction eflect which is capable offurther improving the scavenging and charging of the cylinder.

According to a further feature of the invention the distribution isarranged so that the inlet closes with a suflicient retardation toensure that the cylinder will be fully charged and that any loss ofcharge, through the exhaust duct due to this additional suction effectwill be compensated- Preferably the said deflecting surfaces will besituated close to the cylinder, since the zone from which the body ofgases issuing from the cylinder returns is itself situated very near theexhaust .oriflce of the cylinder, and the device must be situatedbetween the exhaust orifice and this zone before it can exert its actionin preventing the return of the burnt gases to the I device.

Figure 4 shows another modified form of exhaust device. In Figures 2, 3and 4 the arrows indicate the displacement of the gases during theiroutward andreturning or whirling movement at high' speed. The arrows infull lines indicate forward movement, and the arrows in dot and dashlines" indicate return movement.

By way of, example and with reference to Fi ure 1, it is assumed thatthe invention is applied to an engine having a cylinder 1, in whichslides a piston 2, actuating the crank shaft through the medium of'aconnecting rod 3. l is the inlet duct, and 5 the inlet valve controlledfor instance by a push rod and rocker arm 8, to open in the requiredmanner.

- The exhaust duct I opens to the cylinder through one or more ports 8uncovered by the piston 2 when it approaches bottom dead centre.Thisengine may .be of the explosion type, in which case it will be fedthrough the duct I with carburetted mixture, or it may be of thecompressionignition type, in which case it will be through an injector#9.

In this figure it is assumed that the deflecting surfaces, which,according to the invention are arranged or formed in the exhaust duct,are situated' closely adjacent the cylinder in a portion I of thelatter.

- The axis 2- 2 of the exhaust duct is preferably set downwardly so thatit forms a relatively acute angle awith the axis Y--Y of the cylinder,as shown in the figure. More generally, the exhaust duct will be so setrelatively to the cylinder, as to impart the smallest possible change ofdirection to the burnt gases issuing from the cylinder, that is sayitocheck them as little as possible. e

The internal construction of the portion 1' of the exhaust duct is shownin section in Figure 2.

The'inner wall of the duct 1 comprises a 5 toroidal cavity 9, oppositewhich is arranged a deflector member I0, situated upon the axis 2-4.This deflector has a conical portion Ilia the apex of which faces thecylinder i and the surface of this cone is so set as to guide the burntY gases, when they issue from the cylinder, towards the torus 9, asshown by the arrows F1.

The gases guided by the inner. wall of the torus, as well as by aportion lilb of the deflector III which completes this torus are trappedwithin the torus and whirl in the direction of the arrows F2 and form anobturating plug. When the whirling movement comes to an end, the gasesissue to the exterior through a free 1 After this whirling mass has beenformed by the initial portion of the gases the following portion canalso pass directly through the space H without entering the torus 9, byfollowing the path indicatedby the arrows Fa. This portion returns inthe direction F 1, whereuponit encounters the downside end of thedeflector it which is formed, as indicated at lilc, fprdeflecting thereturning mass into the torus 9 in the direction F 2. r

This returning fraction of the gases then encounters the plug formed bythe whirling mass at F2. It is thereby prevented from returning to thecylinder and rebounds from this plug in the direction of exhaust Figure3 illustrates a modification comprising, in the wall of the exhaustduct, a torus 9 similar to that in the form of construction previouslydescribed, and opposite this torus, a de flector l2 constituting twowalls I211, I217, which also guide the gases in the directions F1-Fa.

The difference relative to the preceding form of construction resides inthe fact that the downside end of the deflector is shaped, at iZc, as aportion of a torus, so as to trap the gases which have passed the torus8 in the direction F; and have returned in the direction F 1, and tocause them to form a second plug F 3, or again to 5 send them, in thedirection F 4, tangentially to the first whirling plug so that theyreinforcethe latter instead of running the risk of destroying it, as inthe first embodiment in which they encounter the. whirling mass radiallyIn the modification illustrated in Figure 4, the torus 8 formed by theinner wall of the exhaust duct, terminates, on the downside, in aconical incline l3.

The deflector I, has, on the upside, two parts ila-llbwhich deflect thegases in the directions Fr-F2. so as to form a whirling plug asdescribed; 0n the downside, it has a part llc parallel, or nearlyparallel, to the wall II. I

Under these conditions, the fraction of the, gases which has-escaped asshown by F: and has returned in the direction F 1, is guided between thetwo walls ilc-ll, in the direction F 5, so as to enter the torus .9tangentially and to form an eddy Fc which is added to the eddy F; andreinforces the obturating plug formed by the whirling mass.

In these embodiments, a gaseous obturating space H existing between thedeflector i0 and 1 .the edge of thetorus 9.

plug is formed by a whirling motion imparted 7s r the cylindersubstantially as a mass in an inter-- during their forward movement.

In'the above examples, one cylinder only has been considered, but anysuitable arrangements may of course be provided for rendering theinvention application to a multi-cylinder engine.

l. Methodof controlling two-stroke cycle internal combustion engines,which comprises es tablishing communication between the cylinder andexhaust system during the firing stroke, providing for the issuance ofthe burnt gases from val of time shorter than that which would berequired for the burnt gases to expand down to the ambient pressure byadiabatic flow, whereby the mass of gases moves outward and thereafterreturns, permitting the free and unrestricted outward motion of theissuing mass of burnt gases, maintaining the admission orifice closeduntil the said issuance of the mass of burnt gases is in full progress,admitting fresh charge into the cylinder when the said issuance of theburnt gases is in full progress and causes a suction effect to beexertedin the cylinder, while the exhaust port is still open, and imparting awhirl- -ing motion to the issuing mass of burnt gases before it reachesthe zone from which the return of the burnt gases would occur, wherebythe return of the burnt gases to the cylinder is hindered.

2. Method of controlling two-stroke cycle internal combustion engines,which comprises establishing communication betweenthe cylinder andexhaust system during the firing stroke, providing for the issuance ofthe burnt gases from the cylinder substantially as a mass in an intervalof time shorter than that which would be requiredvfor the burnt gases toexpand down to the ambient pressure by adiabatic flow, whereby the massof gases moves outward and thereafter returns, permitting the free andunrestricted outward motion of the issuing mass of burnt gases,maintaining the admission orifice closed until the said issuance of themass of burnt gases is in full progress, admitting fresh charge. intothe cylinder when the said issuance of the burnt gases is' in fullprogress and causes a suction effect to be exerted in the cylinder,while the exhaust port is still open, imparting a whirling motion to aportion of the issuing mass of burnt gases before said mass reaches thezone from which the return of the burnt gases would occur, andpermitting thefree and unrestricted outward motion of the remainingportion of the mass of burnt gases to the limit of its outward travel,whereby the latter portion thereafter returns towards the cylinder andrebounds from said whirling portion without appreciable lossfin velocityin the direction of exhaust.

3. Method as claimed in claim 2 including imparting a whirling motion tothe second mentioned portion of the mass of burnt gases on its returnmotion.

4. In a two-stroke cycle internal combustion engine having an exhaustconduit, wherein the burnt gases are discharged from the cylinder intothe exhaust conduit substantially as a mass in an interval of timeshorter than that which would be required for the burnt gases to expanddown to the ambient pressure by adiabatic flow,

whereby the said mass moves outwardly and thereafter returns,- the saidexhaust conduit providing a free passage for the burnt gases to thelimit of outward travel of said mass, and wherein a 2,aoc,1os V to thetotality of or a portion of the burnt gases 3 an inlet is opened for theintroduction of fresh charge into the cylinder while the exhaust port isstill open, and when the said issuance of the burnt gases is in fullprogress and causes a suction effect to be exerted in the cylinder, theprovision of means in the'exhaust conduit for imparting a whirlingmotion to the issuing mass of burnt gases before it reaches the zonefrom a which the return would occur, whereby the return of the burntgases to the cylinder is hindered.

.5. In a two-stroke cycle internal combustion engine having an exhaustconduit, wherein the burnt gases are discharged from the cylinder intothe exhaust conduit substantially as a mass in an interval of timeshorter than that which would be required for the burnt gases to expanddown to the ambient pressure by adiabatic flow, whereby. the said massmoves outwardly and thereafter returns, the said exhaust conduitproviding afree passage for .the burnt gases to the limit of outwardtravel of saidmass, and wherein an inlet is opened for the introductionof fresh charge into the cylinder while the exhaust port is still openand when the said issuance of the burnt gases is in full progress andcauses a suction effect to be exerted in the cylinder, the provision ofmeans in the exhaust conduit for imparting a whirling motion to aportion of the issuing mass of burnt gases before said mass reaches thezone from which the return of the burnt gases would occur, andpermitting the free and unrestricted outward motion of the remainingportion of the mass of burnt gases to the limit of its outward travel,whereby the latter portion thereafter returns towards the cylinder andrebounds from said whirling portion without appreciable loss in velocityin the direction of exhaust.

6. In a two-stroke cycle internal combustion engine having a cylinder, acrank shaft, a piston moving in this cylinder and connected to saidcrank shaft, inlet and exhaust orifices on the cylinder for introducingfresh charge and for discharging the products of combustionrespectively, and wherein for recharging the cylinder the burnt gasesare allowed to leave the cylinder substantially as a mass in an intervalof time shorter than that which would be required for the burnt gases toexpand down to the ambient pressure by adiabatic flow, whereby the saidmass moves outwardly and thereafter returns and the fresh charge isallowed to enter the cylinder when the issuance of the burnt gases is infull progress and causes a suction eifect to be exerted at the inletorifice, and while the exhaust port is still open, an exhaust conduitleading from said exhaust orifice, a toroidal cavity in said exhaustconduit adjacent the cylinder and a deflector body within said exhaustconduit arranged to direct the issuing mass of burnt gases tangentiallyinto said cavity, whereby a whirling gaseous plug consisting of at leasta portion of the issuing mass of burnt gases is formed in said toroidalof the burnt'gases to cylinder is hindered.

'7. In a two-stroke cycle internal combustion engine having a cylinder,a crank shaft, a piston moving in this cylinder and connected to saidcrank shaft, inlet and exhaust orifices on the cylinder for introducingfresh charge and for discharging the products of combustionrespectively, and wherein for recharging the cylinder the burnt gasesareallowed toleave the cylinder substantially as a mass in an interval oftime cavity before the said gases reach the zone from which the returnwould occur whereby the return the burnt gases to expand down to theambient pressure by adiabatic fiow, whereby the said mass movesoutwardly and thereafter returns and the fresh charge is allowed toenter; the cylinder when the issuance of the burnt gases is in fullprogress and causes a suction effect to be exerted at the inlet orifice,and while the exhaust port is still open, an exhaust conduit leadingfrom said exhaust orifice, a toroidal cavity in said exhaust conduitadjacent the cylinder and a deflector body within said exhaust conduitarranged to direct the issuing mass oi burnt gases tangentially intosaid cavity, whereby a whirling gaseous plug consisting of at least aportion of the issuinz mass oi burnt gases is formed in said toroidalcavity before the said gases reach the zone from which the return wouldoccur, and arranged to deflect any returning burnt gases tangentiallyinto said cavity whereby the return of the burnt gases to cylinder ishindered.

8. In a two-stroke cycle internal combustion engine having a cylinder, acrank shaft, a piston moving in this cylinder and connected to saidcrank shaft, inlet an'dexhaust orifices on the cylinder for introducingfresh charge and for discharging the products of combustionrespectively, and wherein for recharging the cylinder the burnt gasesare allowed to leave the cylinder substantially as a mass in an intervalof time shorter than that which would be required for the burnt gases toexpand down to the ambient pressure by adiabatic flow, whereby the saidmass moves outwardly and thereafter returns and the shorter than thatwhich would be required for I fresh charge is allowed to enter thecylinder when the issuance of the burnt gases is in full progress andcauses a suction eiiect to be exerted at the inlet orifice, and whilethe exhaust port is still open, an exhaust conduit leading from saidexhaust orifice, a toroidal cavity in said exhaust conduit adjacent thecylinder and a deflector body within said exhaust conduit arranged todirect the issuing mass oi burnt gases tangentially into said cavity,whereby a whirling gaseous plug consisting of at least a-portion of theissuing mass of burnt gases is formed in said toroidal cavity before thesaid-gases reach the zone from which the return would occur, andarrangedto deflect any returning burnt gases radially into said cavitywhereby the return of the burnt gases to cylinder is hindered.

9. The combination'as claimed in claim '7, wherein the deflector body isin the form of two cones with their bases in contact.

10. The combination as claimed in claim vll. wherein the deflector bodyis in the form oi two coneswith their bases in contact. a

11. The combination as claimed in claim 6, whereinthe deflector body hasa progressively decreasing confll'ii fl-tion in the direction 0! theengine cylinder and is'providedwith steroidal cavity directed awayiromthe cylinder, whereby any returning burnt gases form a whirling gaseousplug in said toroidal cavity in the deflector body and are then directedtangentially into the toroidal cavity inthe exhaust conduit.

mom manner.

